EP1225756A1 - Verfahren zur Herstellung eines Bildes - Google Patents

Verfahren zur Herstellung eines Bildes Download PDF

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Publication number
EP1225756A1
EP1225756A1 EP01300025A EP01300025A EP1225756A1 EP 1225756 A1 EP1225756 A1 EP 1225756A1 EP 01300025 A EP01300025 A EP 01300025A EP 01300025 A EP01300025 A EP 01300025A EP 1225756 A1 EP1225756 A1 EP 1225756A1
Authority
EP
European Patent Office
Prior art keywords
image
intensity
offset
values
exposure time
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP01300025A
Other languages
English (en)
French (fr)
Inventor
Philip Atkin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Synoptics Ltd
Original Assignee
Synoptics Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Synoptics Ltd filed Critical Synoptics Ltd
Priority to EP01300025A priority Critical patent/EP1225756A1/de
Priority to US10/038,569 priority patent/US7760264B2/en
Publication of EP1225756A1 publication Critical patent/EP1225756A1/de
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/40—Picture signal circuits
    • H04N1/407—Control or modification of tonal gradation or of extreme levels, e.g. background level
    • H04N1/4072—Control or modification of tonal gradation or of extreme levels, e.g. background level dependent on the contents of the original
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T5/00—Image enhancement or restoration
    • G06T5/40—Image enhancement or restoration using histogram techniques
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T5/00—Image enhancement or restoration
    • G06T5/50—Image enhancement or restoration using two or more images, e.g. averaging or subtraction
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/70—Circuitry for compensating brightness variation in the scene
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00—Indexing scheme for image analysis or image enhancement
    • G06T2207/10—Image acquisition modality
    • G06T2207/10056—Microscopic image

Definitions

  • the present invention relates to a method of obtaining an image and, more particularly, a method of obtaining a substantially linear representation of the brightness of an image having a wide dynamic range.
  • CCD charge-coupled device
  • Digital electronic cameras and other similar imaging devices and systems often use CCD (charge-coupled device) sensors, and work by converting incident photons into charge and accumulating the charge in each pixel for the duration of the exposure.
  • CCD charge-coupled device
  • imaging devices impose limits on the dynamic range of the signal they can capture. In particular, image details in the regions which are either too dark or too bright cannot be captured.
  • the charge in each cell on to which part of an image is imposed is read out and converted into a number representing its intensity or brightness via an analogue-to-digital converter.
  • Averaging of this kind is well known in the art but it does not resolve the problem of saturated areas and dark areas and therefore the present invention discards the values for these pixels from the average, such that only pixels having significant values, that is those well away from the dark and light limits, are considered when averaging the images together.
  • the present invention is aimed at overcoming the shortcomings of the prior art methods.
  • a method of creating an image which includes the steps of:
  • the invention provides for an image to be formed over a wider dynamic range than that of the basic sensor and A-to-D converter and enables the image to be a linear representation of the brightness of the original scene whilst taking into account all the available data and with an optimal signal-to-noise ratio. It also allows an image series to be captured automatically to cover a wide range of exposure times as the number of saturated and zero output pixels is a natural output from each step, so that the sequence can be chosen to cover the entire dynamic range of the specimen automatically rather than arriving, by iteration, at the optimal single exposure time for the whole specimen which is the technique currently employed in the art.
  • the choice of the exposure times T n is very important. For practical cameras, the exposure time is subject to limits and not all exposure times are possible within those limits. As part of the implementation of the present invention, it is required to determine those pixels which are saturated.
  • the operation of a system incorporating the invention can be broken down into three phases: adjustment, capture and analysis. By counting those pixels which are saturated and those for which there is a zero output for a particular frame, the implementation can determine whether the frame is generally over- or underexposed.
  • the "best" single exposure time for the specimen is selected. This selection process is either performed manually via viewing unmodified digital image directly on screen or automatically from the frequency histogram of the intensity levels of the image.
  • the number of pixels at the limits may be monitored. If the exposure time is reduced to a point where no pixels are saturated then there is no more information to be obtained by any further reduction in exposure time. Similarly, if the exposure time is increased to the point where most pixels are saturated there is little point in any further increase. In the presence of noise, it may be worth going a little beyond each of these limits so as to increase the number of valid samples for the averaging.
  • This approach can be subject to two problems: sometimes the ratio between the successive exposure times is not precisely known and there is often an offset present in the camera electronics or in the analogue to digital converter which results in a further offset to each image.
  • each image can be transformed to match the scale and offset of the other.
  • the gradient is the ratio of the two exposure times and the offset is a constant for all pixels.
  • sL is the number of pixels which is saturated in at least one of the images.
  • each image can be transformed to match the scale and offset of the first in the series.
  • Figure 1 is a general view of the apparatus.
  • the system as implemented in the example includes a camera 1 (in the particular example, a JVC KY-F50E camera).
  • the camera 1 output signals are digitized by analogue to digital converters which form part of a framestore board 2 (a Synoptics Prysm framestore) fitted within a personal computer 3 (a Gateway 2000 PC with a 500 MHz Pentium II processor and 256 MB RAM running Windows 98) and then the digital image 4 is placed in the computer's memory and may be displayed on a monitor 5.
  • a framestore board 2 a Synoptics Prysm framestore
  • personal computer 3 a Gateway 2000 PC with a 500 MHz Pentium II processor and 256 MB RAM running Windows 98
  • Control of the system was achieved using software written in Visual Basic and C++ using Synoptics Image Objects to handle the display and processing functions.
  • the "best" single exposure time for the specimen object is selected.
  • This selection process can either be performed via the system displaying on screen the unmodified digital image direct from the camera 1 and allowing the user to select an exposure time which is reasonably rapid yet long enough that sufficient of the contrast in the specimen can be seen or the exposure time may be determined automatically from the frequency histogram of the intensity levels of the image.
  • the data in these memory areas is stored in high precision format in order to avoid data degradation due to rounding or truncation.
  • the exposure time selected during the adjustment phase is then used as a starting point.
  • An image is acquired using this exposure time.
  • a is taken as 1 and b as zero
  • w is 1 for those pixels having an "in range" value and zero otherwise, and the summations identified above are initialised with the values indicated.
  • the exposure time is then increased by approximately a factor of 2, and another image acquired.
  • This process can be repeated to resume for the same starting exposure time but decrease in the exposure time for each iteration until more than a given percentage of the spatial locations have an intensity less than v min .
  • the ratio of the two accumulation values is calculated to form a result image.
  • This image may be subject to a linear rescaling or offset to make it suitable for conversion to a fixed point format image for further processing.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Studio Devices (AREA)
EP01300025A 2001-01-03 2001-01-03 Verfahren zur Herstellung eines Bildes Withdrawn EP1225756A1 (de)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP01300025A EP1225756A1 (de) 2001-01-03 2001-01-03 Verfahren zur Herstellung eines Bildes
US10/038,569 US7760264B2 (en) 2001-01-03 2002-01-02 Method of obtaining an image

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP01300025A EP1225756A1 (de) 2001-01-03 2001-01-03 Verfahren zur Herstellung eines Bildes

Publications (1)

Publication Number Publication Date
EP1225756A1 true EP1225756A1 (de) 2002-07-24

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP01300025A Withdrawn EP1225756A1 (de) 2001-01-03 2001-01-03 Verfahren zur Herstellung eines Bildes

Country Status (2)

Country Link
US (1) US7760264B2 (de)
EP (1) EP1225756A1 (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10307744A1 (de) * 2003-02-24 2004-09-02 Carl Zeiss Jena Gmbh Verfahren zur Bestimmung der Intensitätswerte elektromagnetischer Strahlung
WO2008015176A1 (en) * 2006-07-31 2008-02-07 Hewlett-Packard Development Company, L.P. Electronic image capture with reduced noise
EP2103925A2 (de) * 2008-03-21 2009-09-23 Genetix Corporation Bildgebung mit mehrfacher Belichtung zur automatischen Fluoreszenzmikroskop-Objektträgerabtastung
WO2011087734A1 (en) * 2009-12-22 2011-07-21 Eastman Kodak Company Method for creating high dynamic range image
CN113869291A (zh) * 2021-12-02 2021-12-31 杭州魔点科技有限公司 基于环境亮度调节人脸曝光度的方法、系统、装置和介质

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7167574B2 (en) * 2002-03-14 2007-01-23 Seiko Epson Corporation Method and apparatus for content-based image copy detection
US7532804B2 (en) * 2003-06-23 2009-05-12 Seiko Epson Corporation Method and apparatus for video copy detection
US7486827B2 (en) * 2005-01-21 2009-02-03 Seiko Epson Corporation Efficient and robust algorithm for video sequence matching
JP2008028957A (ja) * 2006-07-25 2008-02-07 Denso Corp 車両用画像処理装置
WO2008088249A1 (en) * 2007-01-17 2008-07-24 Hemocue Ab Apparatus for determining positions of objects contained in a sample
SE530789C2 (sv) * 2007-01-17 2008-09-09 Hemocue Ab Apparat och metod för positionsbestämning av objekt vilka inryms i ett prov

Citations (5)

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Publication number Priority date Publication date Assignee Title
EP0387817A2 (de) * 1989-03-16 1990-09-19 Konica Corporation Elektronische Standbild-Kamera
US5309243A (en) * 1992-06-10 1994-05-03 Eastman Kodak Company Method and apparatus for extending the dynamic range of an electronic imaging system
US5828793A (en) 1996-05-06 1998-10-27 Massachusetts Institute Of Technology Method and apparatus for producing digital images having extended dynamic ranges
US6038038A (en) 1994-08-24 2000-03-14 Xerox Corporation Method for determining offset and gain correction for a light sensitive sensor
WO2000078038A1 (en) * 1999-06-16 2000-12-21 Microsoft Corporation A system and process for improving the uniformity of the exposure and tone of a digital image

Family Cites Families (4)

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EP0106265B2 (de) * 1982-10-07 1992-08-26 Kabushiki Kaisha Toshiba Bilddatenverarbeitungssystem
AU597485B2 (en) * 1987-04-22 1990-05-31 John Lysaght (Australia) Limited Non-contact determination of the position of a rectilinear feature of an article
US5801773A (en) * 1993-10-29 1998-09-01 Canon Kabushiki Kaisha Image data processing apparatus for processing combined image signals in order to extend dynamic range
US7050094B2 (en) * 2000-10-26 2006-05-23 Micron Technology, Inc. Wide dynamic range operation for CMOS sensor with freeze-frame shutter

Patent Citations (5)

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Publication number Priority date Publication date Assignee Title
EP0387817A2 (de) * 1989-03-16 1990-09-19 Konica Corporation Elektronische Standbild-Kamera
US5309243A (en) * 1992-06-10 1994-05-03 Eastman Kodak Company Method and apparatus for extending the dynamic range of an electronic imaging system
US6038038A (en) 1994-08-24 2000-03-14 Xerox Corporation Method for determining offset and gain correction for a light sensitive sensor
US5828793A (en) 1996-05-06 1998-10-27 Massachusetts Institute Of Technology Method and apparatus for producing digital images having extended dynamic ranges
WO2000078038A1 (en) * 1999-06-16 2000-12-21 Microsoft Corporation A system and process for improving the uniformity of the exposure and tone of a digital image

Non-Patent Citations (3)

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Title
BRIAN C MADDEN: "Extended Intensity Range Imaging", INTERNET CITATION, 17 December 1993 (1993-12-17), XP002422049, Retrieved from the Internet <URL:http://citeseer.ist.psu.edu/cache/papers/cs/12888/http:zSzzSzwww.cis. upenn.eduzSz~maddenzSz366.pdf/madden93extended.pdf> [retrieved on 20070226] *
GROSSBERG M D ET AL: "High dynamic range from multiple images: Which exposures to combine?", PROCEEDINGS OF THE EIGHT IEEE INTERNATIONAL CONFERENCE ON COMPUTER VISION. (ICCV). NICE, FRANCE, OCT. 13 - 16, 2003; [INTERNATIONAL CONFERENCE ON COMPUTER VISION], LOS ALAMITOS, CA : IEEE COMP. SOC, US, vol. CONF. 9, 13 October 2003 (2003-10-13), XP002330392, ISBN: 978-0-7695-1950-0 *
ROBERTSON M A ET AL: "Dynamic range improvement through multiple exposures", IMAGE PROCESSING, 1999. ICIP 99. PROCEEDINGS. 1999 INTERNATIONAL CONFERENCE ON - KOBE, JAPAN 24-28 OCT. 1999, IEEE, PISCATAWAY, NJ, USA, vol. 3, 24 October 1999 (1999-10-24), pages 159 - 163, XP010368909, ISBN: 978-0-7803-5467-8, DOI: 10.1109/ICIP.1999.817091 *

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10307744A1 (de) * 2003-02-24 2004-09-02 Carl Zeiss Jena Gmbh Verfahren zur Bestimmung der Intensitätswerte elektromagnetischer Strahlung
WO2008015176A1 (en) * 2006-07-31 2008-02-07 Hewlett-Packard Development Company, L.P. Electronic image capture with reduced noise
CN101523897B (zh) * 2006-07-31 2011-12-14 惠普开发有限公司 具有降低噪声的电子图像捕获
US8264574B2 (en) 2006-07-31 2012-09-11 David Grosvenor Electronic image capture with reduced noise
EP2103925A2 (de) * 2008-03-21 2009-09-23 Genetix Corporation Bildgebung mit mehrfacher Belichtung zur automatischen Fluoreszenzmikroskop-Objektträgerabtastung
EP2103925A3 (de) * 2008-03-21 2013-02-20 Genetix Corporation Bildgebung mit mehrfacher Belichtung zur automatischen Fluoreszenzmikroskop-Objektträgerabtastung
WO2011087734A1 (en) * 2009-12-22 2011-07-21 Eastman Kodak Company Method for creating high dynamic range image
US8737755B2 (en) 2009-12-22 2014-05-27 Apple Inc. Method for creating high dynamic range image
CN113869291A (zh) * 2021-12-02 2021-12-31 杭州魔点科技有限公司 基于环境亮度调节人脸曝光度的方法、系统、装置和介质
CN113869291B (zh) * 2021-12-02 2022-03-04 杭州魔点科技有限公司 基于环境亮度调节人脸曝光度的方法、系统、装置和介质

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US20020186305A1 (en) 2002-12-12
US7760264B2 (en) 2010-07-20

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